Thomas Menouillard

Explicit Dynamic Finite Element Method for Failure with Smooth Fracture Energy Dissipations

A numerical method for dynamic failure analysis through the phantom node method is further developed. A distinct feature of this method is the use of the phantom nodes with a newly developed correction force scheme. Through this improved approach, fracture energy can be smoothly dissipated during dynamic failure processes without emanating noisy artifact stress waves. This method is implemented to the standard 4-node quadrilateral finite element; a single quadrature rule is employed with an hourglass control scheme in order to decrease computational cost and circumvent difficulties associated with the subdomain integration schemes for cracked elements. The effectiveness and robustness of this method are demonstrated with several numerical examples. In these examples, we showed the effectiveness of the described correction force scheme along with the applicability of this method to an interesting class of structural dynamic failure problems.

Correction force for releasing crack tip element with XFEM and only discontinuous enrichment: How to smoothly release the crack tip element with only discontinuous enrichment in XFEM?

This paper deals with numerical crack propagation and makes use of the extended finite element method in the case of explicit dynamics. The advantage of this method is the absence of remeshing. The use of XFEM with Heaviside functions only gives a binary description of the crack tip element: cut or not. Here, we modify the internal forces with a correction force in order to smoothly release the tip element while the virtual crack tip travels through an element. This avoids creating non physical stress waves and improves the accuracy of the evaluation of the stress intensity factors during propagation.